"First Principles"

Many people have commented on the op-ed's use of the phrase "first principles." This is a common phrase in conservative and libertarian writing. Its use, in and of itself, doesn't suggest authorship. 

However, an amicus brief to the Supreme Court, apparently written by Rosen, does include the phrase twice:

"Indeed, it is these very values that often lead to court decisions quashing exercises of censorial power that violate the first principles undergirding our constitutional republic."

"Such a rule would reaffirm this Court's robust protection of the very free-expression rights that in many ways can be said to be the first principle underlying our constitutional experiment in democracy."

[Note, the second quote includes an odd hyphenation, "free-expression rights", a stylistic feature I noted in the NYT op-ed.]

UPDATE 9/13/2018:

Jeffrey A. Rosen uses the term "first principles" in his column from the Summer 2016 issue of Administrative & Regulatory Law News:

And that, perhaps, is a reminder that the Section usefully takes us back to first principles on occasion.